Image display apparatus, image display method, and computer-readable storage medium

ABSTRACT

An image display apparatus according to an embodiment of the present invention includes: a moving unit configured to move a display position of an image displayed on a display screen; a setting unit configured to set a compressed image display area on the display screen; and a compression unit configured to, in a case where the display position of the image is moved by the moving unit, compress a part of the image extending off the display screen and a part of the image displayed in the compressed image display area so that these parts fit within the compressed image display area, and to display a compressed image in the compressed image display area on the display screen.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image display apparatus, an imagedisplay method, and a computer-readable storage medium, and, moreparticularly, to an image display technique.

2. Description of the Related Art

In recent years, there have been increased opportunities for displayingdata for third parties using a large screen display in a meeting orpresentation. For example, various types of data such as textual data,table data, and graphical data, which are created using applicationsoftware for a personal computer, are displayed for third parties usinga large screen display such as a front projector or a rear projector. Insuch a case, a multi-screen display function of displaying a pluralityof images, which are sent from different personal computers or from apersonal computer and a video apparatus, at the same time can beeffectively used.

The multi-screen display function is generally used in television sets.As illustrated in FIG. 11, using the multi-screen display function, afirst screen 110 of full screen size and a second screen 120 of reducedsize which is reduced so that the second screen 120 fits within apredetermined area can be displayed.

However, in the case of a general multi-screen display function, asillustrated in FIG. 11, since the second screen 120 is displayed infront of the first screen 110, a portion of the first screen 110 underthe display area of the second screen 120 is hidden and invisible.

In order to improve a visual effect by arranging important imageportions of a plurality of displayed screens, it is desirable that thedisplay areas of the first screen 110 and the second screen 120 befreely movable. For example, Japanese Patent Laid-Open No. 6-30335discloses a display method of moving a first screen so as not to overlapwith a second screen.

In the method disclosed in Japanese Patent Laid-Open No. 6-30335, a timeof Lm is added to a data writing time at which data is written into amemory so as to determine a data reading time at which the data is readout from the memory as illustrated in FIG. 12, so that a displayed image110′ is shifted to the left as illustrated in FIG. 13. On the otherhand, by subtracting the time of Lm from the data writing time so as todetermine the data reading time as illustrated in FIG. 14, the displayedimage can be shifted to the right.

However, since the image displayed after a display position has beenmoved extends off a screen area, a part of the image becomes invisible.Accordingly, it is difficult to see the entire area of the image. Inorder to see the entire area of the image, a method of compressing theimage so as to fit the entire area of the image within a limited displayarea that has been changed in accordance with the movement of thedisplay position can be considered. However, in this case, the aspectratio of the image is changed, or a part of the image the detailed viewof which is required is also reduced in size. This makes it difficult tosee displayed information.

SUMMARY OF THE INVENTION

The present invention provides an image display apparatus and an imagedisplay method which are capable of displaying all the informationcontained within an image without making it difficult to see theinformation.

An image display apparatus according to an embodiment of the presentinvention includes: a moving unit configured to move a display positionof an image displayed on a display screen; a setting unit configured toset a compressed image display area on the display screen; and acompression unit configured to, in a case where the display position ofthe image is moved by the moving unit, compress a part of the imageextending off the display screen and a part of the image displayed inthe compressed image display area so that these parts fit within thecompressed image display area, and to display a compressed image in thecompressed image display area on the display screen.

An image display method according to an embodiment of the presentinvention is a method for an image display apparatus. The image displaymethod includes: moving a display position of an image displayed on adisplay screen; setting a compressed image display area on the displayscreen; and compressing, in a case where the display position of theimage is moved, a part of the image extending off the display screen anda part of the image displayed in the compressed image display area sothat these parts fit within the compressed image display area, anddisplaying a compressed image in the compressed image display area onthe display screen.

A computer-readable storage medium according to an embodiment of thepresent invention stores computer-executable instructions for: moving adisplay position of an image displayed on a display screen; setting acompressed image display area on the display screen; and compressing, ina case where the display position of the image is moved, a part of theimage extending off the display screen and a part of the image displayedin the compressed image display area so that these parts fit within thecompressed image display area, and displaying a compressed image in thecompressed image display area on the display screen.

According to an embodiment of the present invention, in a case where adisplay position of an image displayed on a display screen is moved, apart of the image extending off the display screen and a part of theimage displayed in a compressed image display area are compressed sothat these parts fit within the compressed image display area, and acompressed image is displayed in the compressed image display area onthe display screen. Accordingly, all the information contained withinthe image can be displayed without making it difficult to see theinformation. As a result, display flexibility can be improved.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically illustrating an exemplaryconfiguration of an image display apparatus according to a firstembodiment of the present invention.

FIG. 2 is a diagram illustrating a display example of a screen accordingto the first embodiment of the present invention when the screen ismoved to the left.

FIG. 3 is a diagram illustrating an operation key according to the firstembodiment of the present invention.

FIG. 4 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the firstembodiment of the present invention is performed.

FIG. 5 is a diagram illustrating a display example of a screen accordingto a second embodiment of the present invention when the screen is movedto the right.

FIG. 6 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the secondembodiment of the present invention is performed.

FIG. 7 is a diagram illustrating a display example of a screen accordingto a third embodiment of the present invention when the screen isupwardly moved.

FIG. 8 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the thirdembodiment of the present invention is performed.

FIG. 9 is a diagram illustrating a display example of a screen accordingto a fourth embodiment of the present invention when the screen isdownwardly moved.

FIG. 10 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the fourthembodiment of the present invention is performed.

FIG. 11 is a diagram illustrating a display example of a screen using amulti-screen display function in the related art.

FIG. 12 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory is performed in screen displayposition movement in the related art.

FIG. 13 is a diagram illustrating a display example of a screen inscreen display position movement in the related art.

FIG. 14 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory is performed in screen displayposition movement in the related art.

FIG. 15 is a block diagram illustrating an exemplary hardwareconfiguration of a multi-window system in an image display apparatusaccording to a fifth embodiment of the present invention.

FIG. 16 is a block diagram illustrating a window processing sectionincluded in an image display apparatus according to the fifth embodimentof the present invention.

FIGS. 17A, 17B, and 17C are diagrams illustrating display examples of ascreen according to the fifth embodiment of the present invention whenthe screen is moved to the left.

FIG. 18 is a flowchart describing a window process according to thefifth embodiment of the present invention.

FIGS. 19A and 19B are diagrams illustrating display examples of a screenaccording to a sixth embodiment of the present invention.

FIGS. 20A and 20B are diagrams illustrating display examples of a screenaccording to the sixth embodiment of the present invention.

FIG. 21 is a flowchart describing a window process according to thesixth embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Various embodiments of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 1 is a block diagram schematically illustrating an exemplaryconfiguration of an image display apparatus according to a firstembodiment of the present invention. Referring to FIG. 1, an imagedisplay apparatus according to the first embodiment includes an imagesignal input section 10, a scaling section 20 for enlarging or reducingan input image, a frame memory 30, an image display section 40 includinga display device and a driver for the display device, a control section50 for controlling an image display apparatus including the scalingsection 20, and an operating section 60 for performing a controloperation of the image display apparatus. The scaling section 20includes a reduction interpolation unit 21 and an enlargementinterpolation unit 22.

If an input image is reduced, the reduction interpolation unit 21performs reduction interpolation processing upon image signalscorresponding to an input image by performing predetermined filteringbased on a reduction ratio controlled by the control section 50, andstores the image signals in the frame memory 30. The enlargementinterpolation unit 22 reads out the image signals stored in the framememory 30, and outputs the image signals to the image display section 40without processing them.

On the other hand, if an input image is enlarged, the reductioninterpolation unit 21 stores image signals corresponding to an inputimage in the frame memory 30 without processing them. The enlargementinterpolation unit 22 reads out the image signals stored in the framememory 30, performs enlargement interpolation processing upon the imagesignals by performing predetermined filtering based on an enlargementratio controlled by the control section 50, and outputs the imagesignals to the image display section 40.

If any of the reduction interpolation processing and the enlargementinterpolation processing are not performed, an input image is output tothe image display section 40 as same-magnification image signals. Eachof the reduction interpolation processing, the enlargement interpolationprocessing, and the writing/reading of data in/from the frame memory 30is performed under the control of the control section 50.

An input image (image signal) input from the image signal input section10 is digital data including a horizontal synchronization signal Hs, avertical synchronization signal Vs, and a pixel clock signal DCK.Writing of data in the frame memory 30 is performed in synchronizationwith these synchronization signals and the pixel clock signal. That is,each dot position (an address in the horizontal direction) is updated insynchronization with the pixel clock signal DCK, each scanning lineposition (an address in the vertical direction) is updated insynchronization with the horizontal synchronization signal Hs, and eachframe is updated in synchronization with the vertical synchronizationsignal Vs.

The reading of data from the frame memory 30 is performed insynchronization with a horizontal synchronization signal Hs2, a verticalsynchronization signal Vs2, and a pixel clock signal DCK2 which aregenerated by a reading synchronization signal generation unit (notillustrated) included in the scaling section 20. These readingsynchronization signals and the pixel clock signal are output to theimage display section 40, and are also used as synchronization signalsfor the display device therein. The scaling section 20 performs thereduction interpolation processing and the enlargement interpolationprocessing based on a data writing address and a data reading addresswhich are controlled by the control section 50.

Next, an image display method according to the first embodiment will bedescribed with reference to FIGS. 2 and 3. First, a screen move mode isset by operating an operation key included in the operating section 60.In the screen move mode, a screen display position is moved inaccordance with the number of times the operation key is pressed, whichis illustrated in FIG. 3 and is included in the operating section 60, ora pressing duration of the operation key.

For example, as illustrated in FIG. 2, on an image display device(display screen) having Lh pixels in the horizontal direction and Lvpixels in the vertical direction, an image 111 having the same number ofpixels as the image display device is input. As illustrated using animage 112, a display position is moved to the left in the horizontaldirection by a distance Lml. At that time, an area of the image displaydevice from the left end thereof to a position apart from the left endby a distance Lcl in the horizontal direction is set as a compressedimage display area.

In this case, a part of the input image 111 in an area from the left endthereof to a position apart from the left end by a distance (Lcl+Lml) inthe horizontal direction is compressed for display so that the part fitswithin the area of the image display device from the left end thereof tothe position apart from the left end by the distance Lcl in thehorizontal direction. Accordingly, after the display position has beenmoved, in the area of the image display device from the left end thereofto the position apart from the left end by the distance Lcl in thehorizontal direction, an image obtained by compressing the part of theinput image 111 in the area from the left end thereof to the positionapart from the left end by the distance (Lcl+Lml) in the horizontaldirection at a compression ratio of Lcl/(Lcl+Lml) is displayed.

On the other hand, after the display position has been moved, in an areaof the image display device from the position apart from the left endthereof by the distance Lcl in the horizontal direction to a positionapart from the left end by a distance (Lh−Lml) in the horizontaldirection, a part of the input image 111 on the right side of theposition apart from the left end thereof by the distance (Lcl+Lml) inthe horizontal direction is displayed without being compressed. Afterthe display position has been moved, in an area of the image displaydevice on the right side of the position apart from the left end thereofby the distance (Lh−Lml) in the horizontal direction, for example, ablack blank image is displayed.

FIG. 4 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thefirst embodiment is performed.

Referring to FIG. 4, Hs1 denotes an input horizontal synchronizationsignal, DCK1 denotes an input pixel clock signal, DATA1 denotes an inputimage signal, Hs2 denotes an output horizontal synchronization signal,DCK2 denotes an output pixel clock signal, and DATA2 denotes an outputimage signal.

If a display position is not moved in the horizontal direction, anaddress Whs corresponding to the number of pixel clocks between afalling edge of the input horizontal synchronization signal Hs1 and thestart of the effective image area of an input image is stored in theframe memory 30 as an input image signal functioning as a horizontaldata writing start address. Input image signals corresponding to thenumber of effective pixels are written in the frame memory 30 byincrementing the address Whs until a horizontal data writing address(Whs+Lh) is obtained.

At the time of reading of data from the frame memory 30, based on afalling edge of the output horizontal synchronization signal Hs2, ahorizontal data reading start address Rhs is set. The image signalscorresponding to the number of effective pixels are read out from theframe memory 30 by incrementing the address Rhs until a horizontal datareading address (Rhs+Lh) is obtained. Consequently, the input image canbe displayed on the entire area of the image display device.

If the display position is moved to the left by the distance Lml in thehorizontal direction, an address (Whs+Lml) obtained by adding thedistance Lml to the horizontal data writing start address Whs, which isa horizontal data writing start address in a case in which the displayposition is not moved, is set as a horizontal data writing startaddress. Subsequently, reduction interpolation processing is performedupon input image signals obtained in a period corresponding to the sumof the distance Lml and the distance Lcl functioning as the length ofthe compressed image display area in the horizontal direction (a part ofthe input image excluding a normal display area). Image signals arewritten in the frame memory 30 by incrementing the horizontal datawriting start address (Whs+Lml) by a value obtained by multiplying aposition in the input image by Lcl/(Lcl+Lml) until a horizontal datawriting address (Whs+Lml+Lcl) is obtained.

However, since a data writing address is an integer in reality, thehorizontal data writing start address (Whs+Lml) is incremented until thehorizontal data writing address (Whs+Lml+Lcl) is obtained. After aperiod corresponding to (Lml+Lcl) has elapsed from the start of theeffect image area of the input image, image signals are sequentiallyobtained by incrementing the horizontal data writing address(Whs+Lml+Lcl) until a horizontal data writing address (Whs+Lh) isobtained, and are then sequentially written in the frame memory 30.

At the time of reading of data from the frame memory 30, an address(Rhs+Lml) obtained by adding the distance Lml to the horizontal datareading start address Rhs, which is a horizontal data reading startaddress in a case in which the display position is not moved, is set asa horizontal data reading start address. Subsequently, image signalscorresponding to the number of effective pixels Lh are read out byincrementing the horizontal data reading start address (Rhs+Lml) until ahorizontal data reading address (Rhs+Lh+Lml) is obtained.

Consequently, a part of the input image 111 from the left end thereof tothe position apart from the left end by the distance (Lcl+Lml) iscompressed so as to obtain a compressed image, and the compressed imageis displayed in the compressed image display area of the length Lcl onthe display screen. Furthermore, a part of the input image 111 in anarea from the position apart from the left end thereof by the distance(Lcl+Lml) to a position apart from the left end by the distance Lh isdisplayed in the normal display area of the display screen from theposition apart from the left end thereof by the distance Lcl to theposition apart from the left end by the distance (Lh−Lml). In the areaof the display screen from the position apart from the left end thereofby the distance (Lh−Lml) to the position apart from the left end by thedistance Lh, a blank image is displayed.

Thus, if an image display position on a display screen is moved to theleft in the horizontal direction, a part of an image extending off thedisplay screen and a part of the image displayed in a compressed imagedisplay area are compressed for display so that these parts fit withinthe compressed image display area. As a result, all the informationcontained within the image can be displayed without loss of theinformation. In this embodiment, by operating a key included in theoperating section 60, a display position is moved. However, for example,if the image display apparatus includes an operating section including aremote controller, the movement of the display position may be performedby performing a key operation of the remote controller.

Next, a second embodiment of the present invention will be described. Anexample illustrated in FIG. 5 will be described. In this example, on animage display device having Lh pixels in the horizontal direction and Lvpixels in the vertical direction, the image 111 having the same numberof pixels as the image display device is input. As illustrated using animage 113, a display position is moved to the right by a distance Lmr inthe horizontal direction. The exemplary functional configuration of animage display apparatus according to the second embodiment is the sameas that of an image display apparatus according to the first embodiment,and the description thereof will be therefore omitted. An area of theimage display device from the right end thereof to a position apart fromthe right end by a distance Lcr in the horizontal direction is set as acompressed image display area.

In this case, a part of the input image 111 in an area from the rightend thereof to a position apart from the right end by a distance(Lcr+Lmr) in the horizontal direction is compressed for display so thatthe part fits within the area of the image display device from the rightend thereof to the position apart from the right end by the distance Lcrin the horizontal direction. Accordingly, after the display position hasbeen moved, in the area of the image display device from the right endthereof to the position apart from the right end by the distance Lcr inthe horizontal direction, an image obtained by compressing the part ofthe input image 111 in the area from the right end thereof to theposition apart from the right end by the distance (Lcr+Lmr) in thehorizontal direction at a compression ratio of Lcr/(Lcr+Lmr) isdisplayed.

On the other hand, in an area of the image display device from theposition apart from the right end thereof by the distance Lcr in thehorizontal direction to a position apart from the right end by adistance (Lh−Lmr) in the horizontal direction, a part of the input image111 on the left side of the position apart from the right end thereof bythe distance (Lcr+Lmr) in the horizontal direction is displayed withoutbeing compressed. In an area of the image display device on the leftside of the position apart from the right end thereof by the distance(Lh−Lmr) in the horizontal direction, for example, a black blank imageis displayed.

FIG. 6 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thesecond embodiment is performed.

If the display position is moved to the right by the distance Lmr in thehorizontal direction, an address Whs that is a horizontal data writingstart address in a case in which the display position is not moved isset as a horizontal data writing start address.

Until a period corresponding to (Lh−Lmr−Lcr) has elapsed from the startof the effective image area of an input image, image signals aresequentially obtained by incrementing the horizontal data writing startaddress Whs until a horizontal data writing address (Whs+Lh−Lcr−Lmr) isobtained, and are then sequentially written in the frame memory 30.Subsequently, reduction interpolation processing is performed upon inputimage signals obtained in a period corresponding to the sum of thedistance Lmr and the distance Lcr functioning as the length of acompressed image display area in the horizontal direction. Image signalsare written in the frame memory 30 by incrementing the horizontal datawriting address (Whs+Lh−Lcr−Lmr) by a value obtained by multiplying aposition in the input image by Lcr/(Lcr+Lmr) until a horizontal datawriting address (Whs+Lh−Lmr) is obtained.

However, since a data writing address is an integer in reality, thehorizontal data writing address (Whs+Lh−Lcr−Lmr) is incremented untilthe horizontal data writing address (Whs+Lh−Lmr) is obtained.

At the time of reading of data from the frame memory 30, an address(Rhs−Lmr) obtained by subtracting the distance Lmr from a horizontaldata reading start address Rhs, which is a horizontal data reading startaddress in a case in which the display position is not moved, is set asa horizontal data reading start address. Subsequently, image signalscorresponding to the number of effective pixels Lh are read out byincrementing the horizontal data reading start address (Rhs−Lmr) until ahorizontal data reading address (Rhs+Lh−Lmr) is obtained.

Consequently, after the display position has been moved, a blank imageis displayed in an area of the display screen from the left end thereofto a position apart from the left end by the distance Lmr in thehorizontal direction. A part of the input image 111 in an area from theleft end thereof to the position apart from the left end by the distance(Lh−Lcr−Lmr) in the horizontal direction is displayed without beingcompressed in the normal display area of the display screen from theposition apart from the left end thereof by the distance Lmr in thehorizontal direction to a position apart from the left end by a distance(Lh−Lcr) in the horizontal direction. Furthermore, a part of the image111 in an area from the position apart from the left end thereof by thedistance (Lh−Lcr−Lmr) in the horizontal direction to the position apartfrom the left end by the distance Lh in the horizontal direction iscompressed so as to obtain a compressed image, and the compressed imageis displayed in the compressed image display area of the display screenfrom the position apart from the left end thereof by the distance(Lh−Lcr) in the horizontal direction to the position apart from the leftend by the distance Lh in the horizontal direction. Thus, if an imagedisplay position on a display screen is moved to the right in thehorizontal direction, a part of an image extending off the displayscreen and a part of the image displayed in a compressed image displayarea are compressed for display so that these parts fit within thecompressed image display area. As a result, all the informationcontained within the image can be displayed without loss of theinformation.

A third embodiment of the present invention will be described below. Anexample illustrated in FIG. 7 will be described. In this example, on animage display device having Lh pixels in the horizontal direction and Lvpixels in the vertical direction, the image 111 having the same numberof pixels as the image display device is input. As illustrated using animage 114, a display position is upwardly moved in the verticaldirection by a distance Lmu. The exemplary functional configuration ofan image display apparatus according to the third embodiment is the sameas that of an image display apparatus according to the first embodiment,and the description thereof will be therefore omitted. An area of theimage display device from the upper end thereof to a position apart fromthe upper end by a distance Lcu in the vertical direction is set as acompressed image display area.

In this case, a part of the input image 111 in an area from the upperend thereof to a position apart from the upper end by a distance(Lcu+Lmu) in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from the upperend thereof to the position apart from the upper end by the distance Lcuin the vertical direction. Accordingly, in the area of the image displaydevice from the upper end thereof to the position apart from the upperend by the distance Lcu in the vertical direction, an image obtained bycompressing the part of the input image 111 in the area from the upperend thereof to the position apart from the upper end by the distance(Lcu+Lmu) in the vertical direction at a compression ratio ofLcu/(Lcu+Lmu) is displayed.

On the other hand, in an area of the image display device from theposition apart from the upper end thereof by the distance Lcu in thevertical direction to a position apart from the upper end by a distance(Lv−Lmu) in the vertical direction, a part of the input image 111 on thelower side of the position apart from the upper end thereof by thedistance (Lcu+Lmu) in the vertical direction is displayed without beingcompressed. In an area of the image display device on the lower side ofthe position apart from the upper end thereof by the distance (Lv−Lmu)in the vertical direction, for example, a black blank image isdisplayed.

FIG. 8 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thethird embodiment is performed.

Referring to FIG. 8, Vs1 denotes an input vertical synchronizationsignal, Hs1 denotes the input horizontal synchronization signal, DATALdenotes the input image signal, Vs2 denotes an output verticalsynchronization signal, Hs2 denotes the output horizontalsynchronization signal, and DATA2 denotes the output image signal.

If a display position is not moved in the vertical direction, an addressWvs corresponding to the number of horizontal synchronization signalsbetween a falling edge of the input vertical synchronization signal Vs1and the start of the effective image area of an input image is stored inthe frame memory 30 as an input image signal functioning as a verticaldata writing start address. Input image signals corresponding to thenumber of effective lines are written in the frame memory 30 byincrementing the address Wvs until a vertical data writing address(Wvs+Lv) is obtained.

At the time of reading of data from the frame memory 30, based on afalling edge of the output vertical synchronization signal Vs2, avertical data reading start address Rvs is set, and image signalscorresponding to the number of effective lines are read out from theframe memory 30 by incrementing the address Rvs until a vertical datareading address (Rvs+Lv) is obtained. Consequently, the input image canbe displayed on the entire area of the image display device.

If the display position is upwardly moved by the distance Lmu in thevertical direction, an address Wvs, which is a vertical data writingstart address in a case in which the display position is not moved, isset as a vertical data writing start address. Subsequently, reductioninterpolation processing is performed upon input image signals obtainedin a period corresponding to the sum of the distance Lmu and thedistance Lcu functioning as the length of the compressed image displayarea in the vertical direction. That is, image signals are written inthe frame memory 30 by incrementing the vertical data writing startaddress Wvs by a value obtained by multiplying a position in the inputimage by Lcu/(Lcu+Lmu) until a vertical data writing address(Wvs+Lmu+Lcu) is obtained.

However, since a data writing address is an integer in reality, avertical data writing address (Wvs+Lmu) is incremented until thevertical data writing address (Wvs+Lmu+Lcu) is obtained. After theperiod corresponding to (Lmu+Lcu) has elapsed from the start of theeffective image area of the input image, image signals are sequentiallyobtained by incrementing the vertical data writing address (Wvs+Lmu+Lcu)until a vertical data writing address (Wvs+Lv) is obtained, and are thensequentially written in the frame memory 30.

At the time of reading of data from the frame memory 30, an address(Rvs+Lmu) obtained by adding the distance Lmu to the vertical datareading start address Rvs, which is a vertical data reading startaddress in a case in which the display position is not moved, is set asa vertical data reading start address. Subsequently, image signalscorresponding to the number of effective lines Lv are read out byincrementing the vertical data reading start address (Rvs+Lmu) until avertical data reading address (Rvs+Lv+Lmu) is obtained.

Consequently, a part of the input image 111 in an area from the upperend thereof to the position apart from the upper end by the distance(Lcu+Lmu) is compressed so as to obtain a compressed image, and thecompressed image is displayed in the compressed image display area ofthe length Lcu in the vertical direction on the display screen. A partof the image 111 in an area from the position apart from the upper endthereof by the distance (Lcu+Lmu) to a position apart from the upper endby the distance Lv is displayed without being compressed in the normaldisplay area of the display screen from the position apart from theupper end thereof by the distance Lcu to the position apart from theupper end by the distance (Lv−Lmu). Furthermore, in an area of thedisplay screen from the position apart from the upper end thereof by thedistance (Lv−Lmu) to the position apart from the upper end by thedistance LV, a blank image is displayed. Thus, if an image displayposition on a display screen is upwardly moved in the verticaldirection, a part of an image extending off the display screen and apart of the image displayed in a compressed image display area arecompressed for display so that these parts fit within the compressedimage display area. As a result, all the information contained withinthe image can be displayed without loss of the information.

A fourth embodiment of the present invention will be described below. Anexample illustrated in FIG. 9 will be described. In this example, on animage display device having Lh pixels in the horizontal direction and Lvpixels in the vertical direction, the image 111 having the same numberof pixels as the image display device is input. As illustrated using animage 115, a display position is downwardly moved in the verticaldirection by a distance Lmd. The exemplary functional configuration ofan image display apparatus according to the fourth embodiment is thesame as that of an image display apparatus according to the firstembodiment, and the description thereof will be therefore omitted. Anarea of the image display device from the lower end thereof to aposition apart from the lower end by a distance Lcd in the verticaldirection is set as a compressed image display area.

In this case, a part of the input image 111 in an area from the lowerend thereof to a position apart from the lower end by a distance(Lcd+Lmd) in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from the lowerend thereof to the position apart from the lower end by the distance Lcdin the vertical direction. Accordingly, in the area of the image displaydevice from the lower end thereof to the position apart from the lowerend by the distance Lcd in the vertical direction, an image obtained bycompressing the part of the input image 111 in the area from the lowerend thereof to the position apart from the lower end by the distance(Lcd+Lmd) in the vertical direction at a compression ratio ofLcd/(Lcd+Lmd) is displayed.

On the other hand, in an area of the image display device from theposition apart from the lower end thereof by the distance Lcd in thevertical direction to a position apart from the lower end by a distance(Lv−Lmd) in the vertical direction, a part of the input image 111 on theupper side of the position apart from the lower end thereof by thedistance (Lcd+Lmd) in the vertical direction is displayed without beingcompressed. In an area of the image display device on the upper side ofthe position apart from the lower end thereof by the distance (Lv−Lmd)in the vertical direction, for example, a black blank image isdisplayed.

FIG. 10 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thefourth embodiment is performed.

If the display position is downwardly moved in the vertical direction bythe distance Lmd, an address (Wvs−Lmd) obtained by subtracting thedistance Lmd from a vertical data writing start address Wvs, which is avertical data writing start address in a case in which the displayposition is not moved, is set as a vertical data writing start address.

Until a period corresponding to (Lv−Lmd−Lcd) has elapsed from the startof the effective image area of the input image, image signals aresequentially obtained by incrementing the vertical data writing startaddress (Wvs−Lmd) until a vertical data writing address (Wvs+Lv−Lcd−Lmd)is obtained, and are then sequentially written in the frame memory 30.

Subsequently, reduction interpolation processing is performed upon inputimage signals obtained in a period corresponding to the sum of thedistance Lmd and the distance Lcd functioning as the length of thecompressed image display area in the vertical direction. Image signalsare written in the frame memory 30 by incrementing the vertical datawriting address (Wvs+Lv−Lcd−Lmd) by a value obtained by multiplying aposition in the input image by Lcd/(Lcd+Lmd) until a vertical datawriting address (Wvs+Lv−Lmd) is obtained.

However, since a data writing address is an integer in reality, thevertical data writing address (Wvs+Lv−Lcd−Lmd) is incremented until thevertical data writing address (Wvs+Lv−Lmd) is obtained.

At the time of reading of data from the frame memory 30, an address(Rvs−Lmd) obtained by subtracting the distance Lmd from a vertical datareading start address Rvs, which is a vertical data reading startaddress in a case in which the display position is not moved, is set asa vertical data reading start address. Subsequently, image signalscorresponding to the number of effective lines Lv are read out byincrementing the vertical data reading start address (Rvs−Lmd) until avertical data reading address (Rvs+Lv−Lmd) is obtained.

Consequently, in an area of the image display device from the upper endthereof to a position apart from the upper end by the distance Lmd, ablank image is displayed. A part of the input image 111 from the upperend thereof to the position apart from the upper end by the distance(Lv−Lcd−Lmd) is displayed without being compressed in the normal displayarea of the image display device from the position apart from the upperend thereof by the distance Lmd to a position apart from the upper endby the distance (Lv−Lcd). A part of the input image 111 from theposition apart from the upper end thereof by the distance (Lv−Lcd−Lmd)in the vertical direction to a position apart from the upper end by thedistance Lv in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from theposition apart from the upper end thereof by the distance (Lv−Lcd) inthe vertical direction to a position apart from the upper end by thedistance Lv in the vertical direction. Thus, if an image displayposition on a display screen is downwardly moved in the verticaldirection, a part of an image extending off the display screen and apart of the image displayed in a compressed image display area arecompressed for display so that these parts fit within the compressedimage display area. As a result, all the information contained withinthe image can be displayed without loss of the information.

A fifth embodiment of the present invention will be described below.FIG. 15 is a block diagram illustrating a hardware configuration of amulti-window system of an image display apparatus according to the fifthembodiment. This system includes at least the following components: acentral processing unit (CPU) 1001, a hard disk drive (HD) 1002, amemory 1003, a mouse 1004, a keyboard 1005, a media drive 1006, and adisplay section 1007. These components are connected to each other via asystem bus 1010. The HD 1002 stores an OS (Operating System) and anapplication program. The mouse 1004 may be another component such as anon-screen digitizer capable of providing information about coordinateson a screen. The display section 1007 is a section for displaying screeninformation generated by the multi-window system, and does not define adisplay device.

FIG. 16 is a block diagram schematically illustrating a configuration ofan image display apparatus according to the fifth embodiment. Referringto FIG. 16, an image display apparatus according to the fifth embodimentincludes a window processing section 1100. The window processing section1100 includes an operation processing unit 1101, a window processingunit 1102, a window condition setting unit 1103, an image compressionunit 1104, and a window image reconstruction unit 1105. The operationprocessing unit 1101 receives input information from the mouse 1004 orthe keyboard 1005, and performs operation processing in accordance withthe input information. Examples of the operation processing includewindow operation processing such as opening, closing, movement, orresizing of a window, and non-window operation processing such as textinput or cursor control performed for application software operated in awindow.

If the window operation processing is performed, the window processingunit 1102 performs window processing in accordance with inputinformation.

FIGS. 17A, 17B, and 17C are diagrams illustrating display examples whena screen according to the fifth embodiment of the present invention ismoved to the left. Referring to FIG. 17A, on a screen 201 included inthe display section 1007, a window 221 is displayed in front of a window211. An example in which the window 211 is moved to the left so as notto overlap with the window 221 will be described. At that time, thewindow processing unit 1102 moves the window 211 to the left andmonitors whether the moved window 211 is in the display area of thescreen 201. The amount of movement of the window may be determined by auser's operation, or may be set in advance. If the amount of movement islarge and the moved window extends off the display area of the screen201 as illustrated in FIG. 17B, the window processing unit 1102 detectsan area extending off the screen 201.

On the other hand, the window condition setting unit 1103 sets acompressed image display area of the screen 201. In the compressed imagedisplay area, a compressed image obtained by compressing a part of awindow extending off the screen 201 and a part of the window displayedin the compressed image display area in a case where the window is movedso that the parts of the window fit within the compressed image displayarea is displayed. The compressed image display area is set using afixed ratio for each of the number of pixels Lh in the horizontaldirection on the screen 201 and the number of pixels Lv in the verticaldirection on the screen 201. This ratio will be hereinafter referred toas a compressed image display area setting value. It is assumed that acompressed image display area setting value for a compressed imagedisplay area at the left or right end is Hcp, a compressed image displayarea setting value for a compressed image display area at the upper orlower end is Vcp, a compressed image display area at the left or rightend is Lch, and a compressed image display area at the upper or lowerend is Lcv. Compressed image display areas Lch and Lcv are determined asfollows.

Lch=Lh×Hcp/100

Lcv=Lv×Vcp/100

The compressed image display area setting value Hcp for a compressedimage display area at the left end may be different from the compressedimage display area setting value Hcp for a compressed image display areaat the right end. The compressed image display area setting value Vcpfor a compressed image display area at the upper end may be differentfrom the compressed image display area setting value Vcp for acompressed image display area at the lower end.

A compressed image display area may not be set using a ratio for thenumber of pixels Lh in the horizontal direction on the screen 201 or thenumber of pixels Lv in the vertical direction on the screen 201, and maybe directly set using the number of pixels in the horizontal directionor the number of vertical lines on the screen 201.

Alternatively, a compressed image display area may be set using a ratiofor a window 212 that is displayed on the screen 201 without extendingoff the screen 201 after the window 211 has been moved. For example, asillustrated in FIG. 17B, if the window 211 is moved to the left and apart of the window 211 in an area from the left end thereof to aposition apart from the left end by the distance Lml extends off thescreen 201, the number of pixels in the horizontal direction in aremaining part of the window 211 displayed on the screen 201 isrepresented by (Lwh−Lml). At that time, assuming that a compressed imagedisplay area setting ratio is Hwcp and a compressed image display areaat the left end of the screen 201 is Lcl, the compressed image displayarea Lcl is determined by the following equation.

Lcl=(Lwh−Lml)×Hwcp/100

An example in which a window is moved to the left has been described.However, the above-described method can also be applied to cases inwhich a window is moved to the right, and a window is upwardly anddownwardly moved.

Furthermore, a compressed image display area may be set in such a mannerthat an object displayed in a non-compressed image display area of thewindow 212, which is a window displayed in the display area of thescreen 201 after the window 211 has been moved, is identified, and thenthe compressed image display area is determined so as not to include theobject or so as to give priority to display of the object.

The above-described setting for the window condition setting unit 1103can be performed using a menu screen displayed as a user interface viathe operation processing unit 1101.

In FIG. 17B, if the window processing unit 1102 detects the areaextending off the display area of the screen 201, the image compressionunit 1104 generates the window 212. More specifically, the imagecompression unit 1104 reduces, based on the setting of the windowcondition setting unit 1103, an area Lml of the window 211 extending offthe display area of the screen 201 and an area of the window 211displayed in the compressed image display area Lcl of the screen 201 sothat these areas fit within the compressed image display area Lcl asillustrated in FIG. 17C. Subsequently, the window image reconstructionunit 1105 reconstructs the moved window image using a compressed imagegenerated by the image compression unit 1104 and an image outside thecompressed image display area, and displays the reconstructed image inthe display section.

Examples of an image compression method include the following methods: amethod of linearly compressing the area Lml extending off the screen 201and the area displayed in the compressed image display area Lcl using,for example, a compression ratio of Lcl/(Lcl+Lml); a method ofnonlinearly compressing these areas by changing a compression ratio sothat a higher compression ratio is obtained on the side of one end ofthe compressed image display area; a method of detecting a blank image(for example, a black or white image) included in a part of the window211 in the area from the left end thereof to the position apart from theleft end by the distance (Lcl+Lml), and setting a high compression ratiofor an area including the detected blank image or removing the blankimage so as to compress only the remaining part excluding the blankimage for display; and a method of identifying objects displayed in thewindow 211, determining whether the moved window 211 extends off thedisplay area of the screen 201, sequentially compressing spaces betweenthe objects from one end of the display screen in the entire area of thewindow when it is determined that the moved window 211 extends off thedisplay area of the screen 201, and performing any one of theabove-described image compression methods when the moved window 211still extends off the display area of the screen 201 despite theabove-described processing.

Next, a process performed by the window processing section 1100 will bedescribed with reference to a flowchart illustrated in FIG. 18. First,in step S101, the window processing unit 1102 determines whether awindow has been moved. If the window has not been moved (NO in stepS101), the window processing unit 1102 continues to monitor movement ofthe window. If the window has been moved (YES in step S101), in stepS102, the window processing unit 1102 determines whether the movedwindow extends off the display area of the screen 201.

If the moved window does not extend off the display area of the screen201 (NO in step S102), in step S104, the window image reconstructionunit 1105 displays the moved window. If the moved window extends off thedisplay area of the screen 201 (YES in step S102), the image compressionunit 1104 compresses a part of the window extending off the screen 201and a part of the window displayed in a compressed image display area sothat these parts fit within the compressed image display area so as togenerate a compressed image in step S103, and displays a moved windowusing the compressed image in step S104.

Thus, even if a window is moved and the moved window extends off adisplay screen, all the information contained within the window can bedisplayed without loss of the information.

A sixth embodiment of the present invention will be described below. Inthe sixth embodiment, as illustrated in FIGS. 19A and 19B, a borderbetween a compressed image display area and a normal display area isvisible using a slider 300.

The hardware configuration of a multi-window system of an image displayapparatus according to the sixth embodiment and the schematicconfiguration of the image display apparatus are the same as thoseaccording to the fifth embodiment illustrated in FIGS. 15 and 16.

In FIGS. 19A and 19B, a user operates the slider 300 using the mouse1004 so as to change the compressed image display area Lcl, so that awindow 212′ including a compressed image display area Lcl′ is displayedas illustrated in FIG. 19B.

Instead of the slider 300, another method capable of representing theborder between the compressed image display area and the normal displayarea and changing the compressed image display area may be used.Accordingly, as illustrated in FIGS. 20A and 20B, a method of displayinga window frame using different colors may be used. In FIG. 20A, a border310 indicates a border between the compressed image display area and thenormal display area. A color of a window 212 is different from a colorof an area divided off the window 212 using the border 310. A useroperates the border 310 using the mouse 1004 so as to change thecompressed image display area Lcl, so that a window 212″ including acompressed image display area Lcl″ is displayed as illustrated in FIG.20B.

Next, a process performed by the window processing section 1100according to the sixth embodiment will be described with reference to aflowchart illustrated in FIG. 21.

First, in step S201, the window processing unit 1102 monitors whether acompressed image display area in a window has been changed. If there isno change in the compressed image display area (NO in step S201), theprocess proceeds to step S101 in which the window processing unit 1102determines whether the window has been moved. If the window has not beenmoved (NO in step S101), the process returns to step S201 in which thewindow processing unit 1102 continues to monitor the change in thecompressed image display area and movement of the window. If it isdetermined in step S101 that the window has been moved (YES in stepS101), the process from step S102 to step S104 is performed. The processfrom step S102 to step S104 is the same as that according to the fifthembodiment, and the description thereof will be omitted.

If it is determined in step S201 that the compressed image display areahas been changed (YES in step S201), the window image reconstructionunit 1105 reconstructs a window image in step S202 based on the changein the compressed image display area, and displays the reconstructedwindow image in step S104.

As described previously, the compressed image display area can always bechanged as appropriate based on information displayed in a window.

Each step according to the present invention can be achieved in such amanner that pieces of software (programs) are obtained via a network orvarious types of computer-readable storage media and are then executedby a processing apparatus (CPU or processor) in a personal computer orthe like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No.2008-119736 filed May 1, 2008, which is hereby incorporated by referenceherein in its entirety.

1. An image display apparatus comprising: a moving unit configured tomove a display position of an image displayed on a display screen; asetting unit configured to set a compressed image display area on thedisplay screen; and a compression unit configured to, in a case wherethe display position of the image is moved by the moving unit, compressa part of the image extending off the display screen and a part of theimage displayed in the compressed image display area so that these partsfit within the compressed image display area, and to display acompressed image in the compressed image display area on the displayscreen.
 2. The image display apparatus according to claim 1, wherein,assuming that a length of the compressed image display area in a movingdirection of the display position of the image is Lc and a movingdistance of the display position of the image is Lm, the compressionunit compresses an image to be displayed in the compressed image displayarea at a compression ratio of Lc/(Lc+Lm).
 3. The image displayapparatus according to claim 1, wherein the setting unit sets thecompressed image display area on a basis of an amount of movement of thedisplay position of the image moved by the moving unit.
 4. An imagedisplay method for an image display apparatus comprising: moving adisplay position of an image displayed on a display screen; setting acompressed image display area on the display screen; and compressing, ina case where the display position of the image is moved, a part of theimage extending off the display screen and a part of the image displayedin the compressed image display area so that these parts fit within thecompressed image display area, and displaying a compressed image in thecompressed image display area on the display screen.
 5. Acomputer-readable storage medium storing computer-executableinstructions for: moving a display position of an image displayed on adisplay screen; setting a compressed image display area on the displayscreen; and compressing, in a case where the display position of theimage is moved, a part of the image extending off the display screen anda part of the image displayed in the compressed image display area sothat these parts fit within the compressed image display area, anddisplaying a compressed image in the compressed image display area onthe display screen.